Abstract

To determine whether lactalbumin production by normal and neoplastic human mammary tissue is under the same control, the effect of prolactin treatment was studied in organ culture. Of 9 premenopausal normal breast samples, 6 produced lactalbumin in culture, and all 6 responded to prolactin treatment over 4 days. One biopsy of pregnant breast tested also responded to prolactin treatment, producing 200 times more lactalbumin in culture than did normal breast. Two of 4 normal postmenopausal biopsies produced lactalbumin, and one increased synthesis and release after prolonged exposure to prolactin. Of 10 scirrhous carcinomas, 6 produced lactalbumin, but none responded to prolactin treatment. In 2 premenopausal patients, normal breast tissue responded to different concentrations of prolactin, which were without effect on malignant tissue from the same breast.

In summary, lactalbumin production in the samples that we have studied can be stimulated in normal but not in malignant breast tissue. This may indicate an absence or deficiency of prolactin receptors in malignant tissue.

Footnotes

↵1 This work was supported by grants from the Medical Research Council, the West Midlands Regional Health Authority, and the University of Birmingham Endowment Fund.

↵2 To whom requests for reprints should be addressed, at Department of Medicine, Queen Elizabeth Hospital, University of Birmingham, Edgbaston, Birmingham B15 2TH, England.